UV raman spectroscopy of H2-air flames excited with a narrowband KrF laser

Shirley, John A.

doi:10.1007/bf00332323

Cited by 28 publications

(3 citation statements)

References 10 publications

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“…The laser intensity in our experiments (100-500 MW/cm2cm-') therefore corresponds to about 10% saturation and to a depletion of the initial rotational state after about ten predissociation lifetimes. However, the ground state replenishment by rotational relaxation is very rapid [35] and would explain why only at considerably higher laser intensities slight deviations from linearity are observed [25]. Although depletion of the vibrational ground state is possible for laser pulse durations of several tens of ns [16,22], we conclude from the observed linearity of fluorescence that this should not constitute a major problem under our conditions.…”

Section: Resultsmentioning

confidence: 69%

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Absolute Temperature Fields in Flames by 2D‐LIF of OH Using Excimer Lasers and CARS Spectroscopy

Arnold

Lange

Bouché

et al. 1992

Ber Bunsenges Phys Chem

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A tunable KrF-excimer laser was used to obtain temperature fields in a laminar, premixed atmospheric pressure flame by 2D-LIF of OH. Relative temperatures were obtained first from the intensity ratio of two sequentially excited rotational lines of the OH (A2Z+ -X2n) transition in the (3-0) band near 248 nm. Because the u' = 3 level is predissociative, this excitation scheme is less sensitive to collisional quenching than lower vibrational levels of OH (A22'). Fluorescence from lower lying, non-predissociative vibrational levels of OH (populated by vibrational transfer) was effectively suppressed by narrow spectral filtering of the (3-2) band of OH. Absolute temperatures were determined by calibration at one point with broadband CARS measurements; the excellent agreement of LIF and CARS profiles suggests that for these conditions and at the present level of accuracy no further corrections are needed. The uncertainty in the 2D-LIF measurements of 7% (for a spatial resolution of 300 pm) is due mainly to shot-to-shot fluctuations of the beam profile. Based on the photon shot noise contribution (less than 1 YO), we estimate that, provided the beam energy and profile are accounted for, single-shot measurements should be feasible with a spatial resolution of 300 pm and a precision of 2%.

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Section: Resultsmentioning

confidence: 69%

“…Tests showed that the fluorescence was linear in the laser intensity range used, in agreement with Refs. [6,25].…”

Section: Methodsmentioning

confidence: 99%

Absolute Temperature Fields in Flames by 2D‐LIF of OH Using Excimer Lasers and CARS Spectroscopy

Arnold

Lange

Bouché

et al. 1992

Ber Bunsenges Phys Chem

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“…11 However, a temperature error may result from the nonlinear relation of temperature and the Rayleigh scattering signal via the effective cross section [Eq. (5)]. It was estimated earlier that the maximum error in the effective Rayleigh scattering cross section due to spatial variationsin the gas compositionis about 10%.…”

Section: Temperature Field Via Two-dimensional Rayleigh Scatteringmentioning

confidence: 99%

Laser-Based Multiparameter Measurements

et al. 1997

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Novel ultraviolet laser-based multidimensional measurement techniques were applied to the burner exit of a H 2 ± air jet engine. Two-dimensional Rayleigh scattering and one-dimensional Raman scattering were used to measure the mean temperature ® eld, the distributions of the majority species H 2 , O 2 , H 2 O, and N 2 , and the turbulence intensity distribution ¾ T /T in the burner exit plane. The wealth of data allows are elucidation of the turbulent mixing and combustion processes inside the burner. For example, the majority species distributions show that unburned H 2 occurred in certain regions in the burner exit plane that were essentially free of O 2 and vice versa. This pattern was constant in time. This means that certain¯ow structures in the burner caused rich mixing in some areas and lean mixing in others, and it explains why overall combustion was not complete in this particular burner.

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The Use of a Flashlamp‐Pumped Dye Laser for Single‐Pulse Spontaneous Raman Scattering in Flames

Prucker¹,

Meier²,

Plath³

et al. 1992

Ber Bunsenges Phys Chem

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A Raman scattering system based on a commercially available, high power flashlamp‐pumped dye laser is presented. Single‐pulse measurements of the temperature and major species concentrations in a stable laminar methane/air flame and in a weakly turbulent H2/air diffusion flame have been performed to assess the measuring precision and detection efficiency of this system. The problem of spatial resolution is discussed and — in this context — the advantages of combined Raman/2D LIF measurements are demonstrated.

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UV raman spectroscopy of H2-air flames excited with a narrowband KrF laser

Cited by 28 publications

References 10 publications

Absolute Temperature Fields in Flames by 2D‐LIF of OH Using Excimer Lasers and CARS Spectroscopy

Absolute Temperature Fields in Flames by 2D‐LIF of OH Using Excimer Lasers and CARS Spectroscopy

Laser-Based Multiparameter Measurements

The Use of a Flashlamp‐Pumped Dye Laser for Single‐Pulse Spontaneous Raman Scattering in Flames

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